Some clarifying questions:

Have you tried using version 2.96 instead of 2.95 (the link to 2.96 is just above this post)?

When you say it can't "see" the files, can you be more specific about what you mean? Where are you expecting the files to appear that they're not appearing?

Do the files have unicode or high-ascii characters in their file names, folder paths, or tags?

Are the files tagged with any sort of security or hidden/system file flags?

Are the files genuine MP3 files, as opposed to some other audio format?

Can you drag the files directly from Windows Explorer and drop them onto the Rio player in Rio Music manager?